Safety belt apparatus for vehicles

ABSTRACT

The invention relates to a safety belt apparatus for vehicles, in particular motor vehicles having at least one safety belt ( 11 ), which is wound to a greater or lesser degree onto a belt reel ( 13 ) rotatably secured on the vehicle chassis ( 14 ) about an axis of rotation ( 12 ) and preferably biased by a spring retraction mechanism, in particular a spiral spring ( 15 ) in the belt winding up direction and/or having a belt draw out- blocking mechanism ( 26, 38; 55, 56, 57 ), which, with an attempted rapid draw out of the safety belt ( 11 ) and/or with in particular accident dependent accelerations and/or deviations of the vehicle position from the normal, horizontal arrangement of the vehicle blocks a further draw out of the safety belt ( 11 ), with a toothed ratchet wheel ( 29 ) being rotationally coupled to the belt reel ( 13 ) and cooperating with a blocking pawl ( 17 ) secured to the housing and movable into an out of engagement, in such a way that with the blocking pawl ( 17 ) moved into engagement with the toothed ratchet wheel ( 29 ), a rolling up movement of the belt reel ( 13 ) by the spring retraction mechanism ( 15 ) is possible, but not a pulling out of the safety belt ( 11 ), and wherein the blocking pawl ( 17 ) is movable into and out of engagement with respect to the toothed ratchet wheel ( 29 ) by a cam ring ( 18 ) concentric to the belt reel axis ( 12 ) via a step down transmission ( 20, 21, 27, 28 ) so that the blocking pawl ( 17 ) is moved out of engagement with a safety belt ( 11 ) which is drawn in to a greater or lesser degree and preferably at least fully drawn in and is movable into engagement with a further drawn out safety belt ( 11 ), preferably with a largely fully drawn out safety belt ( 11 ), wherein a toothed control wheel ( 21 ) is connected to the belt reel ( 13 ) via an eccentric transmission ( 27, 28 ) and has at its periphery a preferably wavelike arrangement of teeth ( 40 ), which is surrounded by an inner toothed ring ( 20 ) fixed to the housing of larger diameter and with complementary teeth ( 41 ), but with a smaller or preferably larger number of teeth, such that the toothed control wheel ( 21 ) stands in meshing arrangement with the inner toothed ring ( 20 ) over a restricted peripheral region and diametrically opposite thereto the two arrangements of teeth ( 40, 41 ) have a radial spacing such that the toothed control wheel ( 21 ) rolls off on the inner toothed ring ( 20 ) on rotation of the belt reel ( 13 ), and wherein the total draw out length of the safety belt ( 11 ) corresponds to an angle of rotation of the toothed control wheel ( 21 ) relative to the axis of rotation ( 12 ) of less than 360° and in particular of substantially 180°. The invention lies in the arrangement by which the toothed control wheel ( 21 ) is rotationally fixedly connected to the cam ring ( 18 ), but radially displaceable in the context of its eccentric movement, with the cam ring ( 18 ) having switching means ( 46, 47 ) along a first angular region ( 45 ) for the engagement and disengagement of the blocking pawl ( 17 ), and at least one switching element ( 49 ) along a second angular region ( 48 ) for at least one further belt draw out dependent switching operation.

[0001] The invention relates to a safety belt apparatus for vehicle, inparticular motor vehicles in accordance with the preamble of patentclaim 1.

[0002] A safety belt apparatus is already known from GB 2 131 279 A inwhich the belt reel actuates a cam ring via a step down transmission. Bymeans of a radial projection the cam ring brings the latching pawl whichcooperates with the toothed ratchet wheel into engagement with thetoothed ratchet wheel when the safety belt is fully drawn out and bringsit out of engagement with the toothed ratchet wheel when the safety beltis fully drawn in. In this manner, after a complete draw out of thesafety belt, only a pulling in of the safety belt is initially possible.This manner of operation is termed ALR operation (automatic lockingretractor operation). After full draw in of the belt, the latching pawlis released by the toothed latching wheel so that now a free draw out ofthe belt is possible. A draw out blocking mechanism now only enters intooperation if an attempt is made to pull the belt out rapidly or ifaccelerations caused by an accident occur. This manner of operation istermed ELR operation (emergency locking retractor operation).

[0003] In this known apparatus the movement of two rotary blocking pawlsinto a surrounding toothed ring fixed relative to the housing onattempted rapid belt pull out takes place in that a rotary clearance isprovided between the belt reel and a toothed ratchet wheel and isremoved by a spring acting between the belt reel and the toothed ratchetwheel, until, on attempted belt pull out, a predetermined rotaryacceleration value is exceeded, which leads to the rotation of thetoothed ratchet wheel lagging behind the rotation of the belt reel,whereby movement of the blocking pawls into engagement is brought about.A precondition for the operability of the known pull out blockingmechanism is thus that the toothed ratchet wheel rotates with delayrelative to the belt reel above a predetermined rotary accelerationvalue. Problematic with this design of the pull out blocking mechanismis the fact that the relative angular position in which the blockingpawls move towards the surrounding inner ring of teeth fixed relative tothe housing cannot be determined in advance. Should the teeth of theblocking pawl and of the inner toothed arrangement by chance stand toothto tooth during the movement into engagement, then an engagement of thepawl teeth into the tooth recesses of the inner ring of teeth is notpossible. Thereafter, an engagement of the blocking pawl into the toothrecesses of the inner ring of teeth is also not ensured with therequired certainty as a result of the generally high speed of rotationof the belt reel.

[0004] EP 0 298 123 A1 describes a safety belt apparatus in which thetransmission which acts on the cam ring is formed as a cycloidaltransmission, such as is also used in a safety belt apparatus known fromU.S. Pat. No. 5,518,197.

[0005] A transmission of this kind is also provided in a safety beltapparatus for motor vehicles of the kind set forth in the preamble ofclaim 1 (DE 196 48 515 A1), with the cam ring only being rotated througha smaller angle in the end positions of the rotating toothed controlwheel, which is just sufficient in order to bring the blocking pawl intoor out of engagement with the toothed ratchet wheel. In this knownapparatus the inner toothed ring and the toothed control wheel arepreferably so formed that the toothed control wheel can execute about aone half revolution between full belt draw in and full belt draw out.

[0006] In all previously known safety belt apparatuses with a switchingcam ring, the latter has the task of bringing the preferably resilientlydeflectable blocking pawl into or out of engagement with the toothedratchet wheel connected to the belt reel.

[0007] The object of the present invention is to provide a furthersafety belt apparatus of the initially named kind in which the cam ringin particular is better exploited.

[0008] In order to satisfy this object, the features of thecharacterizing part of claim 1 are provided.

[0009] The concept underlying the invention is thus to be seen in thefact that at least one further switching function is associated with thecam ring in addition to the function of bringing the resilientlydeflectable blocking pawl into and out of engagement with the toothedratchet wheel in defined manner.

[0010] This is achieved in that the periphery of the cam ring issubdivided into a plurality of regions, preferably two regions, of whichonly one takes on the blocking pawl switching function, whereas theother is available for triggering of further switching functions. Since,in accordance with the invention, a part region of the periphery of thecam ring is to be available for other than blocking pawl switchingpurposes, the angular region which is available for the blocking pawlswitching should be about 180° or somewhat more (up to ca. 200°). Theremainder of the periphery of the cam ring can then be designed, forexample, with magnetic, electrical and/or mechanical elements, so thatone or more further switching functions are triggered at specific anglesof rotation of the cam ring. For this purpose stationary elements, suchas mechanically, electrically or magnetically actuated switches areprovided radially opposite to the relevant part of the peripheralsurface and cooperate with the associated elements on the cam ring.

[0011] A special embodiment in accordance with claim 2 makes provisionfor a belt tensioner to be activated or deactivated by the additionalperipheral surface on the cam ring. It is namely expedient to deactivatea belt tensioner with a non-applied, i.e. drawn-in safety belt, and tofirst activate it when it has been pulled out by a predetermined amountwhich is not, however, sufficient in order to be placed around theoccupant to be protected. In this manner it is ensured that the belttensioner is in any event activated after being placed onto an occupantto be protected. Through the invention, the respective activation ordeactivation can be effected by the same cam ring which is alreadyresponsible for the movement of the blocking pawl in and out ofengagement.

[0012] A preferred practical realization of the concept of the inventioncan be found from claim 3. The use of a tilting element brings about theadvantage that a once set blocking pawl position is maintained until acounterforce acts on the tilting element.

[0013] Advantageous further developments of the invention are defined bythe claims 4 to 8.

[0014] The rotationally fixed and simultaneously radially displaceableconnection of the toothed control wheel to the cam ring expedientlytakes place in accordance with claim 9.

[0015] Further practical embodiments of the invention are characterizedby the claims 10 to 13.

[0016] In order to avoid the disadvantages associated with the pull outblocking mechanism of GB 2 131 279 A, the invention provides thefeatures of claim 14, with expedient further developments beingcharacterized by the claims 15 to 20. In this manner the trouble-freemovement of the teeth of the engageable pawl into the surrounding innerring of teeth can be ensured, since a fixed and predeterminable angularrelationship exists between the angles at which the toothed ratchetwheel is stopped by the blocking tooth and the position of theengageable pawl. The features of claim 20 are a precondition for theprecise movement of the engageable pawl into engagement, i.e. that onexceeding the predetermined acceleration boundary value of the beltreel, and with the belt pull out acceleration which normally prevails,the speed of rotation of the toothed ratchet wheel does not lag behindthat of the belt reel. In this way an undefined engagement of theengageable pawl into the surrounding inner toothed arrangement isreliably avoided. With extremely large belt pull out accelerationscaused by an accident, a rotation of the toothed ratchet wheel is in anyevent stopped by the generally provided blocking mechanism for thetoothed ratchet wheel, which responds to pronounced vehicleaccelerations or decelerations and large deviations of the vehicle fromthe horizontal position. In this case the belt pull out blockingmechanism is thus not required.

[0017] The invention will be described in the following by way ofexample with reference to the drawings in which are shown:

[0018]FIG. 1 a schematic partly sectioned partial view of a belt reelingmechanism in accordance with the invention,

[0019]FIG. 2 a sectional view on the line II-II in FIG. 1 which isslightly reduced relative to FIG. 1, with the belt reel being located inthe rest position with the fully drawn-in safety belt,

[0020]FIG. 3 the same view as FIG. 2 but with the safety belt drawn outby about 600 mm,

[0021]FIG. 4 a further similar view with a fully drawn out safety belt,

[0022]FIG. 5 a like view during the drawing in of the initially fullydrawn out safety belt by the retraction spring, with the safety beltbeing located in the region between full draw-out and a draw-out byabout 600 mm,

[0023]FIG. 6 the same view with the safety belt only drawn out by 600mm,

[0024]FIG. 7 a schematic perspective exploded illustration of theswitching and driving part of a belt reeling mechanism in accordancewith the invention,

[0025]FIG. 8 a schematic sectional view essentially in accordance withthe line VIII-VIII in FIG. 1, and

[0026]FIG. 9 a schematic sectional view essentially in accordance withthe line IX-IX in FIG. 1.

[0027] In accordance with FIGS. 1 and 2 a safety belt 11 is wound ontoan only partly illustrated belt reel 13 with a shaft 13′ and an axis ofrotation 12. A housing 33 is secured in the schematically indicatedmanner to the vehicle chassis 14.

[0028] A toothed ratchet wheel 29 which has ratchet teeth 30 around itsperiphery, which are only partly indicated in FIGS. 2 to 6, sits with arotary clearance of ca. 15° on the right-hand end region of the shaft13′ in FIG. 1, and the plane of the toothed ratchet wheel standsperpendicular to the axis of rotation 12.

[0029] In accordance with FIGS. 1, 8 and 9, a pawl 61 which can be movedinto engagement is rotationally and displaceably mounted in a curved,elongate slot 76 of the toothed ratchet wheel 29 at approximately twothirds of its radius, by a guide spigot 62′ having an axis 62 extendingparallel to the axis of rotation 12.

[0030] In accordance with FIGS. 1 and 9, the engageable pawl 61 is alsopivotally secured to the belt reel 13 about an axis 63 extendingparallel to the axis of rotation 12 radially inwardly of the guidespigot 62′ and offset somewhat in the peripheral direction opposite tothe direction of rotation during belt unwinding. The engageable pawl 61can also execute a restricted pivotal movement in a peripheral cutout 78of the belt reel 13.

[0031] The belt reel 13 is surrounded in the region of the engageablepawl 61 by an inner ring of teeth formed on a steel plate 66, of whichthe tooth recesses 65 are complementary to the teeth 74′ of a pawl arm64 provided radially outwardly at the engageable pawl 61. The engageablepawl 61 is lightly biased in the unblocking direction by anon-illustrated spring.

[0032] In accordance with FIG. 8, a restricted rotary clearance existsbetween the shaft 13′ of the belt reel 13 and the toothed ratchet wheel29, with the toothed ratchet wheel 29 being so biased in the beltunwinding direction relative to the shaft 13′ by means of a spiralspring 67 that an abutment 79 of the shaft 13′ holds the toothed ratchetwheel 29 in the belt unwinding direction at the end of the rotaryclearance 77. The spiral spring 67 should be so powerfully made that inall normally occurring belt pull out accelerations, the rotary movementof the toothed ratchet wheel 29 does not lag behind the rotary movementof the belt reel 13.

[0033] In accordance with FIG. 8 a rotary acceleration lever 38 ispivotally connected to the toothed ratchet wheel 29 about a pivot axis68 extending parallel to and displaced relative to the axis of rotation12 and has two lever arms 38′ and 38″. A resetting spring 70 holds therotary acceleration lever 38 normally in the position shown in fulllines in FIG. 8, where it comes into contact against various abutments71, 72, 73. The rotary acceleration lever 38 is so shaped and arrangedthat it does not move at any desired speeds, but is pivoted with rotaryaccelerations in the belt unwinding direction in FIG. 8 in the clockwisesense about the pivot axis 68, when a predetermined rotary accelerationlimit is exceeded. The resetting spring 70 must likewise be dimensionedin corresponding manner.

[0034] On the lever arm 38′ the rotary acceleration lever 38 has ablocking tooth 69, which can cooperate with the teeth of an innertoothed arrangement 26 of a toothed ring carrier member 25 projectingconcentrically into the arrangement of ratchet teeth 30, when the rotaryacceleration lever 38 is pivoted by a rotary acceleration in the beltunwinding direction above the predetermined rotary acceleration limitvalue, out of the position shown in full lines in FIG. 8 into theposition shown in broken lines which is determined by abutments 71, 74,75.

[0035] As soon as the blocking tooth 60 has moved into engagement in theinner toothed arrangement 26, the toothed ratchet wheel 29 remainsstationary while the belt reel 13 can be rotated further by an amountwithin the rotary clearance 77 with further tensioning of the spring 67.During this, as a result of the displacement of the axis of rotation 63about the axis of rotation 12 and of the displacement of the guidespigot 62′ within the elongate hole 76, the pawl arm 64 of theengageable pawl 61 can be pivoted or shifted, in accordance with FIG. 9,into the blocking position shown in broken lines in FIG. 9, in which theteeth 64′ of the pawl arm 64 engage into the tooth recesses 65′ of theinner ring of teeth 65. Through this engagement, a further rotation ofthe belt reel 13 in the belt winding direction is prevented.

[0036] The ratchet teeth 30 of the toothed ratchet wheel 29 cooperatewith an engageable and disengageable blocking pawl 17 which is shown inFIGS. 2 to 7 and is mounted outside of the periphery of the toothedratchet wheel 29 on the housing 33. On engagement into the ratchet teeth30 of the toothed ratchet wheel 29 the blocking pawl 17 blocks thelatter against rotation in the belt pull-out direction, whereby with afurther attempted pull-out of the safety belt 11 a relative rotationresults between the belt reel 13 and the toothed ratchet wheel 29 withinthe rotary clearance that is provided through ca. 10 to 15°, which leadsto the engagement of the pawl arm 64 into the inner toothed ring 65,whereupon the rotation of the belt reel 13 and thus the further pull-outof the safety belt 11 is also blocked. The toothed ratchet wheel 29,which is of pot-like shape, engages in accordance with FIG. 1 axiallyover a substantially circular ring-like toothed ring support member 25fixed to the housing and having teeth 26 at its inner periphery whichcooperate with a rotary acceleration lever 38. Rotary acceleration lever38 is rotationally fixedly connected to the toothed ratchet wheel 29 andenters into engagement with the inner teeth 26 in a manner which blocksthe further pull-out on attempted rapid pull-out of the safety belt 11.

[0037] In accordance with the FIGS. 2 to 6 an acceleration blockingmechanism 55 fixedly arranged on the housing is located in theperipheral region of the toothed ratchet wheel 29 and has anacceleration sensor 56 which also responds to deviations of the vehicleposition from the normal horizontal arrangement as well as a blockingpawl 57 which, in the drawn-in state, comes out of engagement with oneof teeth 30 of the toothed ratchet wheel 29 and, in the projectingstate, comes into engagement with one of the teeth 30 of the toothedratchet wheel 29. Normally, the blocking pawl 57 is located in theretracted state shown in the FIGS. 2 to 6. If the acceleration sensor 56measures an acceleration of the vehicle which exceeds a predeterminedvalue, such as for example arises during an accident, or if it detects asignificant deviation of the vehicle position from the normal horizontalarrangement, then the blocking pawl 57 is moved in the direction of thetoothed ratchet wheel 29 to such an extent that it comes into engagementwith the latter and thereby moves the control pawl 61 into the innertoothed ring 65 so that from then on the further pull-out of the safetybelt 11 is blocked.

[0038] As soon as the acceleration of the vehicle ends, the blockingpawl 57 comes out of engagement with the toothed ratchet wheel 29again—optionally following a short reverse rotation of the toothedratchet wheel 29 brought about by the spiral spring 15. Accordingly thespring force active between the belt reel 13 and the toothed ratchetwheel 29, i.e. and the control pawl 61, can rotate the toothed ratchetwheel 29 back again relative to the shaft 13′, up to the end of therotary clearance lying in the belt unwinding direction, can in thismanner bring the pawl arm 64 out of engagement with the inner toothedring 65 and can thus release the safety belt 11 for the furtherpull-out.

[0039] Moreover, the toothed ring support member 25 has a furtherapproximately wave-shaped inner toothed ring 20 axially adjoining theinner teeth 26 and having radially inwardly extending teeth 41. Atoothed control wheel 21 is located within the inner toothed ring 20 andhas a smaller diameter and a smaller number of teeth 40. In theillustrated embodiment the inner toothed ring 20 has 27 teeth, thetoothed control wheel 21 in contrast has only 26 teeth.. The diameter ofthe toothed control wheel 21 is just so much smaller than the diameterof the inner toothed ring 20 that, with engagement of the teeth 40, 41on one side of the toothed control wheel, a small radial spacing remainsbetween the inner toothed ring 20 and the toothed control wheel 21 onthe diametrically opposite side.

[0040] The toothed control wheel 21 has a central bearing bore 28 intowhich an eccentric disc 27 engages which is rotationally fixedlyjournalled on the shaft 13′ engages. If the eccentric disc 27 is rotatedin the direction of the arrow in FIG. 2 on pulling out the safety belt11, then the toothed control wheel 21 rolls off on the inner toothedring 20 in the counterclockwise sense. Axially directly adjoining thetoothed control wheel 21 and the eccentric disc 27 there is a cam ring18 having a central bore 19 at the inside. The cam ring 18 is rotatablyarranged on a hollow bearing spigot 16 of the housing fixed relative tothe housing at the side remote from the belt reel 13. A driver pin 24projects from the cam ring 18 in the direction of the toothed controlwheel 21 into a driver recess 23 of the toothed control wheel 21, withno clearance existing in the circumferential direction between thedriver pin 24 and the radial edges of the driver recess 23, whereby arotationally fixed connection is produced between the cam ring 18 andthe toothed control wheel 21. In the radial direction the driver recess23 is, however, extended so far that a radial relative movement betweenthe cam ring 18 and toothed control wheel 21 is possible when thetoothed control wheel 21 executes the eccentric rolling off movement onthe inner toothed ring 20. As an alternative, the driver pin could alsobe provided on the toothed control wheel and the driver recess at thecam ring.

[0041] At its periphery, the cam ring has, in accordance with FIG. 2, afirst angular region 45 and a second angular region 48. Whereas thefirst angular region 45 extends over an angle of about 200°, the secondangular region 48 takes up an angle of about 160°.

[0042] At the start of the angular region 45 lying at the top in FIG. 2there is a radially extending abutment step 46 on the cam ring 18 whichmerges in the counterclockwise sense into a partial, right cylindrical,peripheral surface 51. After an angle of about 140° the peripheralsurface 51 is adjoined in the counterclockwise sense by an abutment step47 which projects radially outwardly by a somewhat smaller amount andwhich merges into a partial, right cylindrical, peripheral surface 54with a somewhat larger diameter than the peripheral surface 51.

[0043] In the clockwise sense and in the peripheral direction aninitially partly right cylindrical cam surface 49 adjoins the abutmentstep 46 and, after an angle of somewhat more than 60°, drops offradially inwardly to the periphery of the peripheral surface 54 via aninclined flank 32.

[0044] In accordance with FIG. 2 a switching arm 52 of a rocker element53 secured to the housing lies in the lower region radially outwardlyagainst the peripheral surface 54 and is tiltable about a rocker axis 44extending parallel to the axis 12. The rocker element 53 has anactuating pin 43 extending parallel to the rocker axis 44 which engagesinto a radial slot 42 of a doubled-armed lever 39 carrying the blockingpawl 17 and having an axis of rotation 34 parallel to the axis 44 inorder to transfer the rocking movement to the blocking pawl 17. AU-shaped spring 31 holds the rocker element 53 in its position whichkeeps the blocking pawl 17 out of engagement with the toothed ratchetwheel 29. The rocker element 53 has a second over-dead center positionin which the blocking pawl 17 is located in engagement with the toothedratchet wheel 29.

[0045] The blocking pawl 17 projects axially in the direction of thebelt reel 11 to such an extent that it can enter radially intoengagement with the ratchet teeth 30 of the toothed ratchet wheel 29from the outside. The blocking pawl 17 is shown out of engagement withthe ratchet teeth 30 in FIGS. 2, 3 and 6 and in engagement with theratchet teeth 30 in FIGS. 4 and 5.

[0046] A micro-switch 50 is mounted on the housing approximatelydiametrically opposite to the rocker element 53 and activates ordeactivates a belt tensioner 35 only schematically indicated in FIG. 1via a control line 37 simply indicated in broken lines in FIG. 1. Thebelt tensioner 35 is triggered on an acceleration of the vehicle causedby an accident and subsequently rotates the belt reel 13, via a clutch36 engaged at the same instant, by an amount in the belt winding-updirection such that the belt 11 firmly contacts the occupant.

[0047] Since, if the safety belt 11 is not being worn, the belttensioner 60 should also not trigger even with accelerations caused byan accident, it is deactivated when the safety belt 11 is drawn in viathe control line 62.

[0048] In accordance with FIGS. 2 to 6 an actuating plunger 22 (see theblack arrow in FIGS. 2, 3) extends radially inwardly from themicro-switch 50 and is located by. the force of the spring 59 in contactwith the switching cam track 49. In the state illustrated in FIG. 3, themicro-switch 50 is actuated in a manner such that it activates the belttensioner 35 via the control line 37 (FIG. 1).

[0049] However, if the cam surface 49 is located in the position shownin FIG. 2, the actuating plunger 22 is pressed radially outwardly at theposition emphasized by a black arrow in order to actuate themicro-switch 50 so that it deactivates the belt tensioner 35 via thecontrol line 37.

[0050] In the fully retracted position of the safety belt 11 shown inFIG. 2 the switching arm 52 contacts the peripheral surface 54 having alarger diameter, or lies closely adjacent it. In this position theblocking pawl 17 is out of engagement with the toothed ratchet wheel 29.At the side of the cam ring 18 remote from the belt reel 13 a spiralspring 15 is arranged in the housing 33 in accordance with FIG. 1. Itexerts a torque in the belt winding-up direction onto the shaft 13′ ofthe belt reel 13 so that the belt is always at least loosely contactedagainst the belted up occupant or fully drawn in when the belt isremoved.

[0051] If now the belt 11 is drawn out (FIG. 3) from the fully drawn-inposition of FIG. 2, then the eccentric disc 27 rotates in the clockwisesense and the toothed control wheel 21 in the counterclockwise sense.During this, the cam ring 18 is likewise driven with it in thecounterclockwise sense. In the region of a belt pull-out of, forexample, 600 mm the plunger 22 passes under the force of the spring 59from the cam surface 49 which projects radially outwardly to thegreatest degree, via the flank 32 extending obliquely to the cam tracksurface 49, to the peripheral surface 54 and switches over themicro-switch 50 into the activating position. During this movement, theswitching arm 52 leaves the peripheral surface 54 but remains, becauseof the action of the spring 31, in the over-dead center position whichcauses the blocking pawl 17 to be out of engagement with the toothedratchet wheel 29.

[0052] As soon as the safety belt 11 is drawn in fully, the abutmentstep 46 contacts the switching arm 52, in accordance with FIG. 4, whichthereby pivots the rocker element 53 in the clockwise sense into theother over-dead center position, which in turn results in a pivotingmovement of the blocking pawl 17 in the counterclockwise sense, and thusthe entry into engagement of the blocking pawl 17 with the teeth 30 ofthe toothed ratchet wheel 29 (black arrow in FIG. 4).

[0053] When the pull-out force on the safety belt 11 subsequently drops,the eccentric disc 27 rotates as a result of the action of the spiralspring 15 in the counterclockwise sense as is shown in FIG. 5. Thetoothed ratchet wheel 21 now executes a movement in the clockwise sense.The abutment step 46 thereby lifts from the switching arm 52 which,however, retains, as a result of its over-dead center position of therocker element 53, the position in which the blocking pawl 17 stands inengagement with the toothed ratchet wheel 29 (black arrow in FIG. 5). Aslong as the belt has been drawn in by about 600 mm, this position of theswitching arm 52 and also of the actuating plunger 22 is maintained,i.e. the actuating plunger 22 remains extended and the micro-switch 50holds the belt tensioner 35 active now as previously.

[0054] Only when the belt pull-out has reduced, in accordance with FIG.6, to below 600 mm does the abutment step 47 contact the switching arm52 which thereby pivots the rocker element 53 in the counterclockwisesense into the opposite over-dead center position (black arrow in FIG.6) and thus brings the blocking pawl 17 out of engagement with thetoothed ratchet wheel 29. At the same time, the actuating plunger 22 isthrust radially outwardly by the radially rising flank and by theswitching cam surface 49 projecting radially outwardly to the greatestdegree, whereby the micro-switch 50 is changed over into a positionwhich deactivates the belt tensioner 35 via the control line 37 (FIG.1). This position of the switching pawl 17 and of the actuating plunger27 does not change anymore when the belt is finally fully retracted intothe position of FIG. 2.

[0055] Thus, in accordance with the invention, through the restrictionof the angular range used for the switching over the blocking pawl toonly somewhat more than 180°, a situation is achieved in which theremaining angular region of ca. 160° can be used for the changeover ofthe micro-switch 50 and optionally for the influencing of the furtherswitching processes.

[0056] In FIG. 7 the components of the belt reeling mechanism of theinvention which are important for the invention are shown in an explodedillustration. A spring biasing element 40 thereby serves as an assemblyaid. A torque transmission member 60 is provided for the transmission ofthe torque of the spiral spring 15 onto the cam disc 27, i.e. the shaft13′ of the belt reel. Reference Numeral List 11 safety belt 12 axis ofrotation 13 belt reel 13′ shaft 14 vehicle chassis 15 spiral spring 16housing-hollow spigot 17 blocking pawl 18 cam ring 19 central bore 20inner toothed ring 21 toothed control wheel 22 actuating pin 23 driverpin 24 driver recess 25 toothed ring support member 26 teeth 27eccentric disc 28 bearing bore 29 toothed ratchet wheel 30 ratchet teeth31 spring 32 flank 33 housing 34 axis of rotation 35 belt tensioner 36clutch 37 control line 38 rotary acceleration lever 38′ lever arm 38″lever arm 39 lever 40 spring bias element 41 tooth 42 radial slot 43actuating pin 44 rocker axis 45 first angular region 46 abutment step 47abutment step 48 second angular region 49 cam surface 50 micro-switch 51peripheral surface 52 switching arm 53 rocker element 54 peripheralsurface 55 acceleration blocking mechanism 56 acceleration sensor 57block pawl 58 hub 59 spring 60 torque transmission member 61 controlpawl 62 axis 63 axis 64 pawl arm 64′ tooth 65 inner toothed ring 65′tooth recess 66 steel plate 67 rotary clearance spring 68 pivot axis 69blocking tooth 70 resetting spring 71 abutments 72 abutment 73 abutment75 abutment 76 elongate hole 77 rotary clearance 78 cutout 79 abutment

1. Safety belt apparatus for vehicles, in particular motor vehicleshaving at least one safety belt (11), which is wound to a greater orlesser degree onto a belt reel (13) rotatably secured on the vehiclechassis (14) about an axis of rotation (12) and preferably biased by aspring retraction mechanism, in particular a spiral spring (15) in thebelt winding up direction and/or having a belt draw out blockingmechanism (26, 38; 55, 56, 57) which, with an attempted rapid draw outof the safety belt (11) and/or with in particular accident dependentaccelerations and/or deviations of the vehicle position from the normal,horizontal arrangement of the vehicle, blocks a further draw out of thesafety belt (11), with a toothed ratchet wheel (29) being rotationallycoupled to the belt reel (13), preferably with a small rotary clearanceand cooperating with a blocking pawl (17) secured to the housing andmovable into an out of engagement, in such a way that with the blockingpawl (17) moved into engagement with the toothed ratchet wheel (29), arolling up movement of the belt reel (13) by the spring retractionmechanism (15) is possible, but not a pulling out of the safety belt(11), and wherein, when the blocking pawl (17) is located in engagementwith the toothed ratchet wheel (29), the toothed ratchet wheel ispreferably rotatable against a spring force relative to the belt reel(13) within the rotary clearance and can bring a control pawl (61)attached to the belt reel (13) into engagement with a toothed ring (65)fixed to the housing, with the blocking pawl (17) being movable into andout of engagement with respect to the toothed ratchet wheel (29) by acam ring (18) concentric to the belt reel axis (12) via a step downtransmission (20, 21, 27, 28) so that the blocking pawl (17) is movedout of engagement with a safety belt (11) which is drawn in to a greateror lesser degree and preferably at least fully drawn in and is movableinto engagement with a further drawn out safety belt (11), preferablywith a largely fully drawn out safety belt (11), wherein a toothedcontrol wheel (21) is connected to the belt reel (13) via an eccentrictransmission (27, 28) and has at its periphery a preferably wave-likearrangement of teeth (40), which is surrounded by an inner toothed ring(20) fixed to the housing of larger diameter and with complementaryteeth (41), but with a smaller or preferably larger number of teeth,such that the toothed control wheel (21) stands in meshing arrangementwith the inner toothed ring (20) over a restricted peripheral region andthe two arrangements of teeth (40, 41) have a radial spacingdiametrically opposite thereto such that the toothed control wheel (21)rolls off on the inner toothed ring (20) on rotation of the belt reel(13), and wherein the total draw outlength of the safety belt (11)corresponds to an angle of rotation of the toothed control wheel (21)relative to the axis of rotation (12) of less than 360° and inparticular of substantially 180°, characterized in that the toothedcontrol wheel (21) is rotationally fixedly connected to the cam ring(18), but radially displaceable in the context of its eccentricmovement, with the cam ring (18) having switching means (46, 47) along afirst angular region (45) for the engagement and disengagement of theblocking pawl (17), and at least one switching element (49) along asecond angular region (48) for at least one further belt drawoutdependent switching operation.
 2. Safety belt apparatus in accordancewith claim 1, characterized in that the switching element is a switchingcam track (49) and actuates a micro-switch (50) fixed relative to thehousing for the activation of a belt tensioner (35) after apredetermined draw outlength of the safety belt (11) from the fullydrawn in state.
 3. Safety belt apparatus in accordance with claim 1 or2, characterized in that the cam ring (18) has a part right cylindricalcircumferential surface (51) along the first angular region (45) at theends of which in the peripheral direction preferably radially outwardlyprojecting abutment steps (46, 47) are provided; which cooperate with aswitching arm (52) of a rocker element (53) acting on the blocking pawlwith two over-dead center positions such that the one abutment step(46), on striking the switching arm (52), pivots the rocker element (53)into the position which brings the blocking pawl (17) into engagementwith the toothed ratchet wheel (29), and the other abutment step (47),on striking the switching arm (52), pivots the rocker element (53) intothe position which brings the blocking pawl (17) out of engagement withthe toothed ratchet wheel (29).
 4. Safety belt apparatus in accordancewith claim 3, characterized in that the abutment step which becomesactive during the drawing inof the belt strikes against the switchingarm (52) of the rocker element (53) when the safety belt (11) is notfully drawn in, and in that the switching arm (52) subsequently liesadjacent or against a preferably part right cylindrical peripheralsurface (54) with a radius greater by the height of the abutment step(47).
 5. Safety belt apparatus in accordance with claim 3 or 4,characterized in that the abutment steps (46, 47) have an angularspacing of 120° to 160°, preferably 130° to 150°, and in particular ofabout 140°.
 6. Safety belt apparatus in accordance with one of thepreceding claims, characterized in that the first angular range (45)amounts to 180° to 220°, preferably 190° to 210°, and in particular toabout 200°.
 7. Safety belt apparatus in accordance with one of thepreceding claims, characterized in that the second angular range (48)amounts to 140° to 180°, preferably 150° to 170°, and in particular toabout 160°.
 8. Safety belt apparatus in accordance with one of thepreceding claims, characterized in that the cam ring (18) has a centralbore (19) rotatably journalled on a central hollow bearing spigot (16)fixed relative to the housing, within which the hub (58) of an eccentricdisc (27) is preferably rotationally journalled, and is preferablyarranged concentric to the belt reel (13).
 9. Safety belt apparatus inaccordance with one of the preceding claims, characterized in that adriver pin (24) extends from the cam ring (18) into a driver recess (23)of the toothed control wheel (21) complementary to it in the peripheraldirection, with the driver recess having a radial extent such that thedriver pin (24) can be freely radially displaced therein during theeccentric movement of the toothed control wheel (21), with it also beingpossible to provide the driver pin on the toothed control wheel and thedriver recess on the cam ring.
 10. Safety belt apparatus in accordancewith one of the claims 2 to 9, characterized in that an actuatingplunger (22) of the micro-switch (59) cooperates with the switching camtrack ((49) in such a way that the micro-switch (50) deactivates thebelt tensioner (35) when the safety belt (11) is drawn in and over arestricted draw out range adjoining it and activates the belt tensionerwith a draw outwhich goes beyond the restricted draw outrange. 11.Safety belt apparatus in accordance with claim 10, characterized in thatthe actuating plunger (22) is thrust radially outwardly by the switchingcam track (49) against the spring force (59) when the safety belt (11)is drawn in and, on the far side of the restricted draw out range, isshifted by spring force (59) onto the switching cam track (49) whichdrops away radially inwardly.
 12. Safety belt apparatus in accordancewith one of the claims 2 to 11, characterized in that the belt tensioneris activated by the micro-switch (50) after a belt draw out of 400 mm to800, preferably 50 mm to 700, and in particular of about 600 mm. 13.Safety belt apparatus in accordance with one of the preceding claims,characterized in that when the belt is drawn in from the fully drawn outstate up to a drawn out belt length of 400 m to 800, preferably 500 mmto 700 mm, and in particular about 600 mm, only a belt draw in ispossible, but not a belt pull out, and in that with a greater belt drawin the blocking pawl (17) is brought out of engagement with the toothedratchet wheel (29) and the belt tensioner is simultaneously deactivated.14. Safety belt apparatus for vehicles, in particular motor vehicleshaving at least one safety belt (11), which is wound to a greater orlesser degree onto a belt reel (13) rotatably secured on the vehiclechassis about an axis of rotation (12) and preferably biased by a springretraction mechanism, in particular a spiral spring (15) in the beltwinding up direction, and having a belt draw out blocking mechanism (26,38), which, with-an attempted rapid draw out of the safety belt (11),blocks a further draw out of the safety belt (11), with a toothedratchet wheel (29) being rotationally coupled to the belt reel (13) witha small rotary clearance (77) and being so spring biased in the beltunwinding direction of rotation of the belt reel (13) relative to thelatter that it is located in the biasing direction at the end of therotary clearance (77), wherein, when the belt draw out blockingmechanism (26, 38) becomes effective and the tension force is maintainedat the safety belt (11), an engageable pawl 61 mounted on the belt reel(13) is brought into engagement with a ring of teeth (65) secured to ahousing, whereupon a further draw out of the safety belt (11) isstopped, in particular in accordance with one or more of the precedingclaims, characterized in that the draw out blocking mechanism has arotary acceleration lever (38) pivotable about a pivot axis (68)extending parallel to the belt reel axis (12), and having, at one end,at least one blocking tooth (69), which, on pivoting of the rotaryacceleration lever (38), can be brought into or out of engagement withan inner toothed arrangement (26) of a toothed ring support member (25)arranged fixed relative to the housing preferably concentric to thetoothed ratchet wheel (29), wherein the rotary acceleration lever (38)is normally held out of engagement with the inner toothed arrangement(26) by a resetting spring (70), but comes into blocking engagement withthe inner toothed arrangement (26), with rotary accelerations in thebelt draw out direction above a predetermined rotary accelerationboundary value.
 15. Safety belt apparatus in accordance with claim 14,characterized in that the rotary acceleration lever (38) has two leverarms (38′, 38″), of which the one is provided with the blocking tooth(69), and the other is arranged relative to the pivot axis (68) suchthat it exerts a torque onto the rotary acceleration lever (38) in theblocking direction, with rotary accelerations in the belt draw outdirection, which leads above the predetermined rotary acceleration limitvalue to a rotation of the rotary acceleration lever (38) against theforce of the spring (70) in the blocking direction.
 16. Safety beltapparatus in accordance with claim 14 or 15, characterized in that thetwo arms (38′, 38″) of the rotary acceleration lever (38) are shaped andare provided with mass such that a torque is only exerted on the rotaryacceleration lever (38) by rotary acceleration, but not by rotaryspeeds.
 17. Safety belt apparatus in accordance with one of the claims14 to 16, characterized in that the abutments (71, 72, 73, 74, 75)restrict the pivotal movements of the rotary acceleration lever (38).18. Safety belt apparatus in accordance with one of the precedingclaims, characterized in that a curved elongate hole (76) is provided inthe toothed ratchet wheel (29) extending substantially radially with aperipheral component and receives a guide spigot (62′) concentric to theaxis (63) of the engageable pawl (61); and in that the engageable pawl(61) is rotatably mounted on the belt reel (13) preferably radiallyinwardly of the guide spigot (62′) about an axis (63) which extendsparallel to the axis (12) of the belt reel (13).
 19. Safety beltapparatus in accordance with one of the preceding claims, characterizedin that the number and arrangement of the teeth of the inner toothedarrangement (26) and of the inner toothed ring (65) are selectedrelative to one another such that on blocking of the rotation of thetoothed ratchet wheel (29) by engagement of the blocking tooth (69) intothe inner toothed arrangement (26), the teeth (64′) of the engageablepawl (61) are aligned with the tooth recesses (65) in the peripheraldirection in such a way that with a relative rotation between the beltreel (13) and the stationary toothed ratchet wheel (29), a problem-freeengagement of the teeth (64′) into the tooth recesses (65′) is ensured.20. Safety belt apparatus in accordance with one of the precedingclaims, characterized in that the rotary clearance spring (67) is sostrongly made that the toothed ratchet wheel (29) is driven with thesame speed of rotation of the belt reel (13) with the normally arisingrotary accelerations of the belt reel (13) in the belt draw outdirection and in that the rotary clearance (77) is first overcomeagainst the force of the rotary clearance spring (67) when the blockingtooth (69) is engaged into the inner toothed arrangement (26).